Electric power devices for energy production and industrial power devices may contain cooling liquids or operating liquids, such as oil. An oil-filled power transformer is an example of such an electric power device containing a cooling or operating liquid. To permanently ensure proper operation of the electric power device, a liquid sample is taken from the cooling or operating liquid at particular intervals of time (e.g., during servicing). A sampling container filled with the liquid sample that has been taken is then transported to a remote laboratory, where extensive diagnosis and analysis of the liquid sample can be performed. The sampling container used may either be bottles made of aluminum, steel, glass or plastic, or else syringes or containers which are open at two ends.
In order to record a precise association between the electric power device, on the one hand, and the liquid sample taken, on the other hand, it is known to write down the relevant data, such as the owner and characterizing data of the electric power device, the location at which the sample is taken and desired analysis values, on a sticker or badge which is mounted on the sampling container. In this case, there is the risk of this badge being lost or this sticker being damaged. Furthermore, it is known to provide a container with a container tag which has a read memory area, which can be read by radio and which allows explicit identification of the container.